From 3572cef24ccbe1ed705d53a2d398d76e9bbd83a4 Mon Sep 17 00:00:00 2001 From: Gus Caplan Date: Tue, 4 Aug 2020 19:10:20 -0500 Subject: [PATCH] Normative: move __proto__ out of annex b --- spec.html | 261 +++++++++++++++++++++++++----------------------------- 1 file changed, 122 insertions(+), 139 deletions(-) diff --git a/spec.html b/spec.html index 7dd4868c0d6..8fc6e3110dd 100644 --- a/spec.html +++ b/spec.html @@ -57,6 +57,17 @@ emu-table td { background: #fff; } + [normative-optional] { + border-left: 5px solid #ff6600; + padding: .5em; + display: block; + background: #ffeedd; + } + [normative-optional]:before { + display: block; + color: #884400; + content: "NORMATIVE OPTIONAL"; + } @@ -12839,7 +12850,7 @@

Syntax

In certain contexts, |ObjectLiteral| is used as a cover grammar for a more restricted secondary grammar. The |CoverInitializedName| production is necessary to fully cover these secondary grammars. However, use of this production results in an early Syntax Error in normal contexts where an actual |ObjectLiteral| is expected.

- +

Static Semantics: Early Errors

PropertyDefinition : MethodDefinition
    @@ -12857,6 +12868,19 @@

    Static Semantics: Early Errors

    This production exists so that |ObjectLiteral| can serve as a cover grammar for |ObjectAssignmentPattern|. It cannot occur in an actual object initializer.

     + + ObjectLiteral : `{` PropertyDefinitionList `}` + + ObjectLiteral : `{` PropertyDefinitionList `,` `}` + +
      +
    • + It is a Syntax Error if PropertyNameList of |PropertyDefinitionList| contains any duplicate entries for *"__proto__"* and at least two of those entries were obtained from productions of the form PropertyDefinition : PropertyName `:` AssignmentExpression. +
      • +
    + +

    The List returned by PropertyNameList does not include string literal property names defined as using a |ComputedPropertyName|.

    +     @@ -13019,18 +13043,25 @@

    Runtime Semantics: PropertyDefinitionEvaluation

    1. Let _propKey_ be the result of evaluating |PropertyName|. 1. ReturnIfAbrupt(_propKey_). - 1. If IsAnonymousFunctionDefinition(|AssignmentExpression|) is *true*, then + 1. If this |PropertyDefinition| is contained within a |Script| that is being evaluated for JSON.parse (see step of JSON.parse), then + 1. Let _isProtoSetter_ be *false*. + 1. Else, If _propKey_ is the String value *"__proto__"* and if IsComputedPropertyKey(|PropertyName|) is *false*, then + 1. Let _isProtoSetter_ be *true*. + 1. Else, + 1. Let _isProtoSetter_ be *false*. + 1. If IsAnonymousFunctionDefinition(|AssignmentExpression|) is *true* and _isProtoSetter_ is *false*, then 1. Let _propValue_ be NamedEvaluation of |AssignmentExpression| with argument _propKey_. 1. Else, 1. Let _exprValueRef_ be the result of evaluating |AssignmentExpression|. 1. Let _propValue_ be ? GetValue(_exprValueRef_). + 1. If _isProtoSetter_ is *true*, then + 1. If Type(_propValue_) is either Object or Null, then + 1. Return ! _object_.[[SetPrototypeOf]](_propValue_). + 1. Return NormalCompletion(~empty~). 1. Assert: _enumerable_ is *true*. 1. Assert: _object_ is an ordinary, extensible object with no non-configurable properties. 1. Return ! CreateDataPropertyOrThrow(_object_, _propKey_, _propValue_). - -

    An alternative semantics for this production is given in .

    -     @@ -26277,6 +26308,91 @@

    Object.prototype.valueOf ( )

    This function is the %ObjProto_valueOf% intrinsic object.

    + + +

    Object.prototype.__proto__

    +

    `Object.prototype.__proto__` is an accessor property with attributes { [[Enumerable]]: *false*, [[Configurable]]: *true* }. The [[Get]] and [[Set]] attributes are defined as follows:

    + + +

    get Object.prototype.__proto__

    +

    The value of the [[Get]] attribute is a built-in function that requires no arguments. It performs the following steps when called:

    + + 1. Let _O_ be ? ToObject(*this* value). + 1. Return ? _O_.[[GetPrototypeOf]](). + +     + + +

    set Object.prototype.__proto__

    +

    The value of the [[Set]] attribute is a built-in function that takes an argument _proto_. It performs the following steps when called:

    + + 1. Let _O_ be ? RequireObjectCoercible(*this* value). + 1. If Type(_proto_) is neither Object nor Null, return *undefined*. + 1. If Type(_O_) is not Object, return *undefined*. + 1. Let _status_ be ? _O_.[[SetPrototypeOf]](_proto_). + 1. If _status_ is *false*, throw a *TypeError* exception. + 1. Return *undefined*. + +     +     + + +

    Object.prototype.__defineGetter__ ( _P_, _getter_ )

    +

    When the `__defineGetter__` method is called with arguments _P_ and _getter_, the following steps are taken:

    + + 1. Let _O_ be ? ToObject(*this* value). + 1. If IsCallable(_getter_) is *false*, throw a *TypeError* exception. + 1. Let _desc_ be PropertyDescriptor { [[Get]]: _getter_, [[Enumerable]]: *true*, [[Configurable]]: *true* }. + 1. Let _key_ be ? ToPropertyKey(_P_). + 1. Perform ? DefinePropertyOrThrow(_O_, _key_, _desc_). + 1. Return *undefined*. + +     + + +

    Object.prototype.__defineSetter__ ( _P_, _setter_ )

    +

    When the `__defineSetter__` method is called with arguments _P_ and _setter_, the following steps are taken:

    + + 1. Let _O_ be ? ToObject(*this* value). + 1. If IsCallable(_setter_) is *false*, throw a *TypeError* exception. + 1. Let _desc_ be PropertyDescriptor { [[Set]]: _setter_, [[Enumerable]]: *true*, [[Configurable]]: *true* }. + 1. Let _key_ be ? ToPropertyKey(_P_). + 1. Perform ? DefinePropertyOrThrow(_O_, _key_, _desc_). + 1. Return *undefined*. + +     + + +

    Object.prototype.__lookupGetter__ ( _P_ )

    +

    When the `__lookupGetter__` method is called with argument _P_, the following steps are taken:

    + + 1. Let _O_ be ? ToObject(*this* value). + 1. Let _key_ be ? ToPropertyKey(_P_). + 1. Repeat, + 1. Let _desc_ be ? _O_.[[GetOwnProperty]](_key_). + 1. If _desc_ is not *undefined*, then + 1. If IsAccessorDescriptor(_desc_) is *true*, return _desc_.[[Get]]. + 1. Return *undefined*. + 1. Set _O_ to ? _O_.[[GetPrototypeOf]](). + 1. If _O_ is *null*, return *undefined*. + +     + + +

    Object.prototype.__lookupSetter__ ( _P_ )

    +

    When the `__lookupSetter__` method is called with argument _P_, the following steps are taken:

    + + 1. Let _O_ be ? ToObject(*this* value). + 1. Let _key_ be ? ToPropertyKey(_P_). + 1. Repeat, + 1. Let _desc_ be ? _O_.[[GetOwnProperty]](_key_). + 1. If _desc_ is not *undefined*, then + 1. If IsAccessorDescriptor(_desc_) is *true*, return _desc_.[[Set]]. + 1. Return *undefined*. + 1. Set _O_ to ? _O_.[[GetPrototypeOf]](). + 1. If _O_ is *null*, return *undefined*. + +     @@ -38407,7 +38523,7 @@

    JSON.parse ( _text_ [ , _reviver_ ] )

    1. Let _jsonString_ be ? ToString(_text_). 1. [id="step-json-parse-validate"] Parse ! UTF16DecodeString(_jsonString_) as a JSON text as specified in ECMA-404. Throw a *SyntaxError* exception if it is not a valid JSON text as defined in that specification. 1. Let _scriptString_ be the string-concatenation of *"("*, _jsonString_, and *");"*. - 1. [id="step-json-parse-parse"] Let _completion_ be the result of parsing and evaluating ! UTF16DecodeString(_scriptString_) as if it was the source text of an ECMAScript |Script|. The extended PropertyDefinitionEvaluation semantics defined in must not be used during the evaluation. + 1. [id="step-json-parse-parse"] Let _completion_ be the result of parsing and evaluating ! UTF16DecodeString(_scriptString_) as if it was the source text of an ECMAScript |Script|. 1. Let _unfiltered_ be _completion_.[[Value]]. 1. [id="step-json-parse-assert-type"] Assert: _unfiltered_ is either a String, Number, Boolean, Null, or an Object that is defined by either an |ArrayLiteral| or an |ObjectLiteral|. 1. If IsCallable(_reviver_) is *true*, then @@ -42947,95 +43063,6 @@

    unescape ( _string_ )

    - -

    Additional Properties of the Object.prototype Object

    - - -

    Object.prototype.__proto__

    -

    `Object.prototype.__proto__` is an accessor property with attributes { [[Enumerable]]: *false*, [[Configurable]]: *true* }. The [[Get]] and [[Set]] attributes are defined as follows:

    - - -

    get Object.prototype.__proto__

    -

    The value of the [[Get]] attribute is a built-in function that requires no arguments. It performs the following steps when called:

    - - 1. Let _O_ be ? ToObject(*this* value). - 1. Return ? _O_.[[GetPrototypeOf]](). - -     - - -

    set Object.prototype.__proto__

    -

    The value of the [[Set]] attribute is a built-in function that takes an argument _proto_. It performs the following steps when called:

    - - 1. Let _O_ be ? RequireObjectCoercible(*this* value). - 1. If Type(_proto_) is neither Object nor Null, return *undefined*. - 1. If Type(_O_) is not Object, return *undefined*. - 1. Let _status_ be ? _O_.[[SetPrototypeOf]](_proto_). - 1. If _status_ is *false*, throw a *TypeError* exception. - 1. Return *undefined*. - -     -     - - -

    Object.prototype.__defineGetter__ ( _P_, _getter_ )

    -

    When the `__defineGetter__` method is called with arguments _P_ and _getter_, the following steps are taken:

    - - 1. Let _O_ be ? ToObject(*this* value). - 1. If IsCallable(_getter_) is *false*, throw a *TypeError* exception. - 1. Let _desc_ be PropertyDescriptor { [[Get]]: _getter_, [[Enumerable]]: *true*, [[Configurable]]: *true* }. - 1. Let _key_ be ? ToPropertyKey(_P_). - 1. Perform ? DefinePropertyOrThrow(_O_, _key_, _desc_). - 1. Return *undefined*. - -     - - -

    Object.prototype.__defineSetter__ ( _P_, _setter_ )

    -

    When the `__defineSetter__` method is called with arguments _P_ and _setter_, the following steps are taken:

    - - 1. Let _O_ be ? ToObject(*this* value). - 1. If IsCallable(_setter_) is *false*, throw a *TypeError* exception. - 1. Let _desc_ be PropertyDescriptor { [[Set]]: _setter_, [[Enumerable]]: *true*, [[Configurable]]: *true* }. - 1. Let _key_ be ? ToPropertyKey(_P_). - 1. Perform ? DefinePropertyOrThrow(_O_, _key_, _desc_). - 1. Return *undefined*. - -     - - -

    Object.prototype.__lookupGetter__ ( _P_ )

    -

    When the `__lookupGetter__` method is called with argument _P_, the following steps are taken:

    - - 1. Let _O_ be ? ToObject(*this* value). - 1. Let _key_ be ? ToPropertyKey(_P_). - 1. Repeat, - 1. Let _desc_ be ? _O_.[[GetOwnProperty]](_key_). - 1. If _desc_ is not *undefined*, then - 1. If IsAccessorDescriptor(_desc_) is *true*, return _desc_.[[Get]]. - 1. Return *undefined*. - 1. Set _O_ to ? _O_.[[GetPrototypeOf]](). - 1. If _O_ is *null*, return *undefined*. - -     - - -

    Object.prototype.__lookupSetter__ ( _P_ )

    -

    When the `__lookupSetter__` method is called with argument _P_, the following steps are taken:

    - - 1. Let _O_ be ? ToObject(*this* value). - 1. Let _key_ be ? ToPropertyKey(_P_). - 1. Repeat, - 1. Let _desc_ be ? _O_.[[GetOwnProperty]](_key_). - 1. If _desc_ is not *undefined*, then - 1. If IsAccessorDescriptor(_desc_) is *true*, return _desc_.[[Set]]. - 1. Return *undefined*. - 1. Set _O_ to ? _O_.[[GetPrototypeOf]](). - 1. If _O_ is *null*, return *undefined*. - -     -     -

    Additional Properties of the String.prototype Object

    @@ -43294,50 +43321,6 @@

    RegExp.prototype.compile ( _pattern_, _flags_ )

    Other Additional Features

    - -

    __proto__ Property Names in Object Initializers

    -

    The following Early Error rule is added to those in . When |ObjectLiteral| appears in a context where |ObjectAssignmentPattern| is required the Early Error rule is not applied. In addition, it is not applied when initially parsing a |CoverParenthesizedExpressionAndArrowParameterList| or a |CoverCallExpressionAndAsyncArrowHead|.

    - - ObjectLiteral : `{` PropertyDefinitionList `}` - - ObjectLiteral : `{` PropertyDefinitionList `,` `}` - -
      -
    • - It is a Syntax Error if PropertyNameList of |PropertyDefinitionList| contains any duplicate entries for *"__proto__"* and at least two of those entries were obtained from productions of the form PropertyDefinition : PropertyName `:` AssignmentExpression. -
      • -
    - -

    The List returned by PropertyNameList does not include string literal property names defined as using a |ComputedPropertyName|.

    -     -

    In the PropertyDefinitionEvaluation algorithm for the production -
    - PropertyDefinition : PropertyName `:` AssignmentExpression -
    - is replaced with the following definition:

    - PropertyDefinition : PropertyName `:` AssignmentExpression - - 1. Let _propKey_ be the result of evaluating |PropertyName|. - 1. ReturnIfAbrupt(_propKey_). - 1. If _propKey_ is the String value *"__proto__"* and if IsComputedPropertyKey(|PropertyName|) is *false*, then - 1. Let _isProtoSetter_ be *true*. - 1. Else, - 1. Let _isProtoSetter_ be *false*. - 1. If IsAnonymousFunctionDefinition(|AssignmentExpression|) is *true* and _isProtoSetter_ is *false*, then - 1. Let _propValue_ be NamedEvaluation of |AssignmentExpression| with argument _propKey_. - 1. Else, - 1. Let _exprValueRef_ be the result of evaluating |AssignmentExpression|. - 1. Let _propValue_ be ? GetValue(_exprValueRef_). - 1. If _isProtoSetter_ is *true*, then - 1. If Type(_propValue_) is either Object or Null, then - 1. Return _object_.[[SetPrototypeOf]](_propValue_). - 1. Return NormalCompletion(~empty~). - 1. Assert: _enumerable_ is *true*. - 1. Assert: _object_ is an ordinary, extensible object with no non-configurable properties. - 1. Return ! CreateDataPropertyOrThrow(_object_, _propKey_, _propValue_). - -     -

    Labelled Function Declarations

    Prior to ECMAScript 2015, the specification of |LabelledStatement| did not allow for the association of a statement label with a |FunctionDeclaration|. However, a labelled |FunctionDeclaration| was an allowable extension for non-strict code and most browser-hosted ECMAScript implementations supported that extension. In ECMAScript 2015, the grammar productions for |LabelledStatement| permits use of |FunctionDeclaration| as a |LabelledItem| but includes an Early Error rule that produces a Syntax Error if that occurs. For web browser compatibility, that rule is modified with the addition of the highlighted text: